“You can think of every language as being an old-growth forest of the mind, a watershed of thought, an ecosystem of social and spiritual possibilities.”

That’s a line that stuck with me from Dr. Wade Davis’s Thomas Conservation Oration, delivered recently at Sydney’s Australian Museum and presented by the Conservancy in partnership with the Thomas Foundation. Davis is a National Geographic Explorer-in-Residence, a position that’s taken him around the globe several times over and put him in touch with some of the world’s oldest, most remote cultures—so he’s someone who knows about social possibilities.

How the full breadth of human experience intersects with the natural world was the focal point of Davis’s oration, which was the third in a series of annual addresses. My interest in having Davis out here to speak stemmed from his deep experience in living and working with diverse cultures. In his speech, he traced the arc of his career and took the audience on a journey from the mountains of Colombia to the Canadian Arctic in order to reveal how cultures are inextricable from the environments where they developed.

That’s a crucial message in Australia, where The Nature Conservancy works hand-in-hand with Indigenous people to conserve the vital natural places that have supported humans on this continent for millennia. The lesson that losses to Indigenous culture damage the environment—and vice versa—is strikingly resonant in a country where Western settlement supplanted peoples that stewarded (and were stewarded by) the land with great care and success.

To me, Davis’s thinking about language’s relationship to the protection of biodiversity—both around the globe and here in Australia—is particularly fascinating. In his speech, Davis noted that the number of languages spoken in the world had declined from 7,000 to 3,500 during the average lifespan of one of his audience members. At the time of British settlement, 670 Indigenous languages and dialects could be heard in Australia—now, that number’s been whittled down to around 20 that are thought to be strong enough to survive.

Losing a language isn’t just losing grammar, syntax and vocabulary—it obliterates expression, leaving a culture unable to articulate its way of knowing. There’s a disturbing parallel to biodiversity loss, here. As anthropologist Russell Bernard puts it, “Any reduction of language diversity diminishes the adaptational strength of our species because it lowers the pool of knowledge from which we can draw.”

To wit: conservation knowledge occupies a particularly prominent place in Indigenous Australian cultures, some of which have been around for more than 40,000 years. Over that time, Indigenous people have developed an intimate knowledge of Australia itself and, in many cases, can tell us more about how to protect the land than any conservation science textbook.

A cohesive theme throughout Wade’s body of work is that all human cultures share the same DNA and have equal cognitive capacity, but that they focus and apply their collective intellect in different ways. This results in different ways of knowing and different conceptions of what it means to be human and alive. For many Westerners, nature occupies too small a place in our worldview; we’ve lost touch with the land and forgotten how to care for it.

“For all of us and for all time, these peoples—like ourselves—represent the collective heritage of humanity, the multiple voices of humanity, and altogether they become our collective geography of hope,” Davis said to conclude his lecture. Davis used his oration to deliver an important reminder: that culture is not trivial and it’s important to listen to those talking on behalf of the Earth, as they have great knowledge and wisdom that’s crucial to humanity.

The director of The Nature Conservancy’s Australia program, Michael Looker is a trained botanist and one of Australia’s leading scientists. Under his direction, the program has protected 8.9 million acres (3.6 million hectares) of biodiversity rich land in Australia through 27 direct land acquisitions.